rough idle, running rich and poorly

[glenn_y]

1995 325i

this problem is intermittent and very inconsistant -- the car will run perfectly then runs rich and very roughly, and then goes back to perfect. this can occur between one startup and another or go for days where it will run badly or great.

the ICV was removed, cleaned, and replaced with new hoses -- little to no change.

when running poorly, i get NO fault readings on the R5/FCX - does this hint at a vacuum leak?

while running properly, if i disconnect the O2 sensor, nothing happens. i presume that something should happen - this is a question?

the car has the 4 terminal o2 sensor. i have taken it off and tested it using a volt meter per the jared fenton article. the readings are very low - .1 and almost no change. this points to the O2 sensor?

any comments will be appreciated. sorry for the long post. i like to know what to change before i just change parts.

glenn

[Patron69]

Glen,
I have a 1994 325i with the same problem. I posted something last month and never received any help. I am currently looking at different avenues. It may be a vacuum leak. I took my car in to a BMW shop and they fixed all of the vacuum leaks. I still have the problem. I replaced my ICV with a new unit, and still no change.
I received the following advice from an expert:
"What you have described sounds exactly like a faulty idle control valve. You have the Bentley E36 3 Series Service Manual, correct? I'd like to you to verify idle control valve function using a digital voltmeter, and I'd also like a pin-out test from the ECU to the idle control valve -- could be a wiring problem or even a corroded connector at the ICV.

I'd also like you to diagnose the intake air temperature sensor at the MAF."

I'll be posting a reply once I finish this troubleshooting.

-Brian

[koya1893]

An old timer trick I learned and from what I read in the forum many have done the same. Injuce "Seafoam" through a vacuum line, prefferebly through the line on the fuel regulator on just put the stuff in a squirt bottle and squirt it at the intake tube. In addition you might want to have injectors clean. make sure it is through direct rail.

Ben